Stockholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended							9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012 Preferred Stock [Member]	Dec. 31, 2011 Preferred Stock [Member]	Sep. 30, 2012 Common Stock [Member]	Dec. 31, 2011 Common Stock [Member]	Sep. 30, 2012 Additional Paid In Capital [Member]	Sep. 30, 2012 Accumulated Deficit [Member]	Sep. 30, 2012 Other Comprehensive Income/(loss) [Member]	Sep. 30, 2012 AXT, Inc. stockholders equity [Member]	Sep. 30, 2012 Noncontrolling interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period			$ 147,049	[1]		$ 3,532	$ 3,532	$ 32	$ 32	$ 191,554	$ (62,157)	$ 5,818	$ 138,779	$ 8,270
Common stock options exercised			276							276			276
Stock-based compensation			873							873			873
Comprehensive income:
Net income	1,444	7,862	6,823		22,217						3,866		3,866	2,957
Net dividends declared by joint ventures			(4,086)											(4,086)
Change in unrealized (loss) gain on marketable securities	9	(191)	115		(218)							115	115
Change in foreign currency translation adjustment, net of tax	(192)	460	119		1,377							73	73	46
Balance, end of period	$ 151,169		$ 151,169			$ 3,532	$ 3,532	$ 32	$ 32	$ 192,703	$ (58,291)	$ 6,006	$ 143,982	$ 7,187

[1] The Condensed Consolidated Balance Sheet at December 31, 2011 has been derived from the audited consolidated financial statements at that date.